Environmentalist Quotes and aphorisms about need John Muir John Muir ,, Bread without flesh is a good diet, as on many botanical excursions I have proved. Tea also may eas... Greta Thunburg Paul Hawken ,, We need to revise our economic thinking to give full value to our natural resources. This revised e... David R. Brower Richard Leakey Richard Leakey Bill McKibben Johan Rockstrom Johan Rockstrom